After the flash version 10 as I can remember, the old method of going to the temp folder /tmp/ and copying the video from there is not working, you will not find it there, It is put there then deleted from disk and treated as a file in memory so this is how to get it. Using the terminal:

pgrep -f flashplayer

this will display the process IDs using flash player, assume the process ID was 3660, then navigate to the process data

This optimus technology is simply the device have two graphics cards, one Intel and the other is the Nvidia one.

This is used to save laptop's battery by disabling the Nvidia card that is relying on GPUs when low graphics processing is needed and doing that on the intel one, and when high performance is needed the work is done on the Nvidia GPUs are redirected to the intel one after being done.